Comparing the Performance of γ-Alumina Nanofiller and Titanium Tetraisopropoxide Catalyst in the Rejuvenation of Water Tree Degraded XLPE Cables

Abstract

This article evaluates the performance of titanium tetraisopropoxide (TTIP) and γ-alumina nanofiller (Al2O3) in rejuvenation and restoration of degraded XLPE underground medium voltage–power distribution cables. These two materials will be injected into aged cables in the form of two rejuvenation composition groups based on silane coupling agents. The injected and aged specimens were then compared in terms of dielectric loss factor (tanδ) measurement, scanning electron microscopy (SEM) analysis, Fourier transform infrared spectroscopy (FTIR) and energy dispersive x-ray (EDX) analysis. After measurement of dielectric loss factor in 7-day intervals, 1 month after the injection of rejuvenation fluids, it was found that the injected cable specimen dielectric loss tangent in the second group, which contained γ-alumina nanofiller, was lower than the specimens injected with TTIP (first group); even their tanδ was lower than the new unused cables. Microstructures of the rejuvenated and aged specimens were compared by means of SEM analysis and the results indicated that titanium and aluminum nanoparticles filled the water-filled microscopic cavities and modified the polymeric insulation surface. FTIR analysis compared the chemical bonds of the insulation layer in injected and aged cables. EDX analysis also detected the element type and value on the treated insulation specimen surface area. Comparing the four afore-mentioned analysis illustrated that both fluids were efficacious in rejuvenation and rehabilitation of degraded XLPE cable insulations. However, γ-alumina nanofiller performs better than TTIP in rejuvenation of degraded XLPE power cables.